Manufacturing method of semiconductor device using peeling

ABSTRACT

The present invention has an object to perform a peeling treatment in a short time. Peeling is performed while a peeling layer is exposed to an atmosphere of an etching gas. Alternatively, peeling is performed while an etching gas for a peeling layer is blown to the peeling layer in an atmosphere of an etching gas. Specifically, an etching gas is blown to a part to be peeled while a layer to be peeled is torn off from a substrate. Alternatively, peeling is performed in an etchant for a peeling layer while supplying an etchant to the peeling layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/276,349, filed Feb. 24, 2006, now U.S. Pat. No. 9,040,420, whichclaims the benefit of a foreign priority application filed in Japan asSerial No. 2005-056308 on Mar. 1, 2005, both of which are incorporatedby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device having a circuitincluding a thin film transistor (hereinafter referred to as a TFT) anda manufacturing method thereof. For example, the invention relates to anelectro-optical device typified by a liquid crystal display devicehaving a liquid crystal display panel, a light emitting display panelincluding an organic light emitting element, or an electronic device onwhich an integrated circuit having an antenna is mounted as a part.

In this specification, a semiconductor device refers to all types ofdevices which can function by using semiconductor characteristics. Anelectro-optical device, a semiconductor circuit, and an electronicdevice are included in the category of all semiconductor devices.

2. Description of the Related Art

Recently, a technique of making a thin film transistor (TFT) using asemiconductor thin film (approximately, having a thickness of severalurn to several hundreds run) formed over a substrate having aninsulating surface has been focused. The thin film transistor is widelyapplied to electronic devices such as ICs and an electro-optical device.Rapid development of a thin film transistor particularly as a switchingelement of an image display device is made.

Though various applications using such an image display device areexpected, an application to portable devices is particularly focused. Aglass substrate or a quartz substrate is currently used in many cases;however, there is a problem in that it is heavy and easily broken. Inaddition, a glass substrate and a quartz substrate are not suitable formass production since they have a difficulty of being increased in size.Thus, formation of a TFT element over a flexible substrate, typically,over a flexible plastic film is tried.

However, since the plastic film has low heat resistance, maximum processtemperature is required to be low. As a result, a TFT having morefavorable electric characteristics than that in the case of forming aTFT over a glass substrate cannot be formed in the present situation.Accordingly, a liquid crystal display device or a light emitting elementusing a plastic film, which has high performance, is not realized.

At the situation, a technique is proposed, in which an element formedover a glass substrate is peeled from the substrate and transferred toanother base material, for example, a plastic film or the like.

The present applicant (the assignee) proposes a peeling and transferringtechnique described in Reference 1 and Reference 2 (Reference 1:Japanese Patent Laid-Open No. H8-288522, and Reference 2: JapanesePatent Laid-Open No. H8-250745). In Reference 1, a technique in which asilicon oxide film to be a peeling layer is peeled by wet etching to beremoved is described. In addition, a technique in which a silicon filmto be a peeling layer is peeled by dry etching to be removed isdescribed in Reference 2.

Further, the present applicant (the assignee) proposes a peeling andtransferring technique described in Reference 3 (Reference 3: JapanesePatent Laid-Open No. 2003-174153). In Reference 3, a technique isdescribed, in which, when a metal layer is formed over a substrate andan oxide layer is laminated thereover, a metal oxide layer of the metallayer is formed at an interface between the metal layer and the oxidelayer and peeling is performed in a subsequent step by using the metaloxide layer.

In addition, the present applicant (the assignee) describes a techniquein Reference 4, in which wind pressure of a gas blown from a nozzle inpeeling, an ultrasonic wave, or the like is used (Reference 4: JapanesePatent Laid-Open No. 2003-163338).

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a structure and amethod of transferring an integrated circuit including a TFT to aflexible substrate in a shorter time than in a conventional way andmanufacturing a semiconductor device with low cost and high yield.

One feature of the invention is to supply an etching gas or an etchant(also refers to an etching liquid or an etching solution) to a peelinglayer (also refers to a separation layer) or an interface thereof so asto promote peeling, when a layer to be peeled is peeled from a substrateby a physical force.

Specifically, a tungsten film (or an alloy film such as a tungstennitride film) to be a peeling layer is formed over a glass substrate bysputtering, and a silicon oxide film is laminated thereover bysputtering. Then, an element such as a TFT is formed over the siliconoxide film, and a protective layer is formed. A plurality of openingportions reaching the peeling layer is formed to introduce an etchinggas or an etchant. Subsequently, the etching gas or the etchant isintroduced from the opening portions, and a layer to be peeled is peeledfrom the substrate with a physical force applied. Further, the peelinglayer is kept supplied with the etching gas or the etchant so as topromote peeling while peeling of the layer to be peeled is conducted.

The etching gas or the etchant used in the invention is typically a gasor a liquid containing halogen (halide), though it depends on a materialof the peeling layer. For example, in a case of using tungsten for thepeeling layer, ClF₃, CF₄, SF₆, NF₃, F₂, or the like is used as theetching gas. For example, when silicon is used for the peeling layer, asolution or the like containing hydrofluoric acid (HF) is used as theetchant. Further, when silicon oxide is used as the peeling layer, asolution or the like containing ammonium hydrogen fluoride (NH₄F) can beused as the etchant.

In addition, peeling may be performed by a physical force afterattaching an auxiliary substrate to the protective layer. There is not aparticular limitation on the auxiliary substrate, as long as it isrigid; however, a substrate having flexibility is preferably used.

By applying a physical force, peeling is performed at an interfacebetween the peeling layer and the layer to be peeled. In addition, theetching gas or the etchant is supplied to the peeling layer to generatea chemical reaction; accordingly, peeling becomes easier to beperformed. The layer to be peeled which has been thus peeled (includingan element such as a TFT) is transferred to a plastic substrate.

“Application of the physical force” in this specification refers toapplying a force by a means recognized by not chemistry but physics,specifically, by a dynamic means or a pneumatic means including aprocess capable of being applied to law of thermodynamics. “Peeling bythe physical force” refers to peeling by an external impact (stress) byusing, for example, a material, the human hand, wind pressure of a gasblown from a nozzle, supersonic wave, or the like.

One feature of a manufacturing method of a semiconductor deviceaccording to the invention disclosed in this specification is to includea first step of forming a peeling layer over a substrate having aninsulating surface; a second step of forming a layer to be peeledincluding a plurality of thin film integrated circuits over the peelinglayer; and a third step of peeling the layer to be peeled provided overthe peeling layer from the substrate in an atmosphere of an etching gas.

In addition, a layer to be peeled can be peeled from a substrate whilebeing blown by an etching gas. One structure of the invention is toinclude a first step of forming a peeling layer over a substrate havingan insulating surface; a second step of forming a layer to be peeledincluding a plurality of thin film integrated circuits over the peelinglayer; and a third step of removing the peeling layer by blowing anetching gas thereto while the layer to be peeled provided over thepeeling layer is peeled from the substrate in an atmosphere of anetching gas.

In addition, a layer to be peeled can be peeled from a substrate in aliquid. One structure of the invention is to include a first step offorming a peeling layer over a substrate having an insulating surface; asecond step of forming a layer to be peeled including a plurality ofthin film integrated circuits over the peeling layer; and a third stepof removing the peeling layer by supplying an etchant while the layer tobe peeled provided over the peeling layer is peeled from the substratein an etchant.

In each structure mentioned above, the peeling layer is a single layerformed of an element selected from Si, W, Ti, Ta, Mo, Cr, Nd, Fe, Ni,Co, Zr, Zn, Ru, Rh, Pd, Os, or Ir, or an alloy material or a compoundmaterial containing the element as its main component. In addition, thepeeling layer is not limited to a single layer in the invention and maybe a laminated layer thereof.

In a case of using Si as the peeling layer, ClF₃, CF₄, SF₆, NF₃, F₂, orthe like can be used as the etching gas. In the case of using Si as thepeeling layer, a tetramethylammonium hydroxide solution called TMAH, aKOH solution, an N₂H₄ solution, an NaOH solution, a CsOH solution, orthe like can be used as the etchant, as well as a solution containinghydrofluoric acid (HF).

Further, in a case of using W, Mo, or Cr as the peeling layer, anaqueous solution containing HNO₃ and (NH₄)₂Ce(NO₃)₆, or the like can beused as the etchant.

In each structure described above, one feature is that the thin filmintegrated circuit includes a TFT, and a CPU can be formed by using theTFT. In addition, by providing an antenna in the thin film integratedcircuit, a semiconductor device having a function of sending andreceiving can be formed.

In addition, by a manufacturing method of the invention, a thin filmintegrated circuit including a TFT can be peeled off from a glasssubstrate and further transferred to a flexible substrate. Bytransferring the thin film integrated circuit including a TFT to theflexible substrate, mass production can be realized, in which many thinfilm integrated circuits are formed over one substrate. Further, bytransferring a thin film integrated circuit to a flexible substrate, asemiconductor device itself, on which the thin film integrated circuitis mounted, can be reduced in weight.

According to the invention, by utilizing both a physical force and achemical reaction, peeling can be smoothly performed in a short time.

BRIEF DESCRIPTION OF DRAWINGS

In the accompanying drawings:

FIGS. 1A and 1B show cross-sections of a manufacturing process of thepresent invention (Embodiment Mode 1);

FIGS. 2A and 2B are a perspective view and a cross sectional view of apeeling apparatus used in a manufacturing process of the presentinvention (Embodiment Mode 2);

FIGS. 3A and 3B show cross-sections of a manufacturing process of thepresent invention (Embodiment Mode 2);

FIGS. 4A and 4B are cross-sections of semiconductor devices (Embodiment1);

FIGS. 5A and 5B are a perspective view and a block diagram of asemiconductor device (Embodiment 2);

FIGS. 6A and 6B are a perspective view of a thin film integrated circuitof the invention and a block diagram of a system using the thin filmintegrated circuit; and

FIGS. 7A to 7F are articles on which thin film integrated circuits ofthe invention are mounted.

DETAILED DESCRIPTION OF THE INVENTION

Embodiment Mode

Embodiment Mode of the present invention is hereinafter described.

(Embodiment Mode 1)

In Embodiment Mode 1, a manufacturing method is described, in which alayer to be peeled including a TFT formed over a glass substrate ispeeled off from the glass substrate and then transferred onto a plasticsubstrate. Here, an example of removing a layer to be peeled with ahalogen gas blowing to a peeling layer in an atmosphere containing ahalogen gas is described.

First, a peeling layer 11 is formed on a glass substrate 10. As thepeeling layer 11, a single layer or a laminated layer formed of anelement selected from W, Ti, Ta, Mo, Cr, Nd, Fe, Ni, Co, Zr, Zn, Ru, Rh,Pd, Os, or Ir, or an alloy material or a compound material containingthe element as its main component can be used. Alternatively, a singlelayer or a laminated layer formed of nitride of the above-describedelement such as titanium nitride, tungsten nitride, tantalum nitride, ormolybdenum nitride can be used. The thickness of the peeling layer 11 is10 nm to 200 nm, preferably 50 nm to 75 nm.

In this embodiment mode, a tungsten (W) film is used as the peelinglayer.

Next, an insulating film is formed over the peeling layer 11. At thistime, an amorphous metal oxide film with a thickness of about 2 nm to 5nm is formed between the peeling layer 11 and the insulating film. Whenpeeling is performed in a subsequent step, the separation occurs insidethe metal oxide film, at an interface between the metal oxide film andthe insulating film, or at an interface between the metal oxide film andthe metal film. The insulating film may be formed of silicon oxide,silicon oxynitride, or a metal oxide material by sputtering. It ispreferable that the thickness of the insulating film be more than abouttwice the thickness of the peeling layer 11, preferably 150 nm to 200nm.

Subsequently, a film formed of a material containing at least hydrogenis formed over the insulating film. As the film formed of a materialcontaining at least hydrogen, a semiconductor film, a nitride film, orthe like can be applied. A semiconductor film is formed in thisembodiment mode. After that, a thermal treatment is performed fordiffusing the hydrogen contained in the film of a material containing atleast hydrogen. This thermal treatment may be performed at a temperatureof 410° C. or higher, and may be performed separately from a formingprocess of a polysilicon film or may be performed together with theforming process of a polysilicon film so as to reduce the number ofsteps. For example, in a case where an amorphous silicon film containinghydrogen is used as the film of the material containing hydrogen andheated to form a polysilicon film, if the thermal treatment is performedat a temperature of 500° C. or higher for crystallization, diffusion ofhydrogen can be performed together with the formation of the polysiliconfilm.

Next, by a known technique, the polysilicon film is etched into adesired shape so that a layer including a plurality of TFTs is formed.For example, a central processing unit (CPU), a microprocessor unit(MPU), or the like can be formed by using TFTs. In addition, an antennaor the like may be formed. The antenna has a function of sending andreceiving electromagnetic field or radio wave. A laminated layerincluding at least a TFT, formed over the peeling layer 11, is called alayer to be peeled 12.

The TFT has a polysilicon film forming a source region, a drain region,and a channel forming region; a gate insulating film which covers thepolysilicon film; a gate electrode formed over the channel formingregion of the polysilicon film; and a source electrode and a drainelectrode which are connected to the source region and the drain regionwith an interlayer insulating film interposed therebetween.

Next, a protective layer 13 is formed. The protective layer 13 is formedby using a material which does not react with a halogen gas (ClF₃) to beused in a subsequent step, for example, an organic resin. The protectivelayer 13 is not necessarily provided. Further, in a case of peeling theprotective layer after attaching it to an auxiliary substrate, theprotective layer is preferably formed of a material which attaches tothe auxiliary substrate well.

Then, dry etching or wet etching is performed by using a mask. In thisetching step, an opening portion 14 reaching the peeling layer 11 isselectively formed in a region except a region provided with the TFT, awiring, or the like, so as to expose the peeling layer 11.Alternatively, the opening portion 14 may be formed by using laserlight, without using a mask. In the case of using laser light, the layerto be peeled or the peeling layer is removed by laser ablation. For thelaser light, a gas laser such as an excimer laser, a CO₂ laser, or anargon laser; a solid laser such as a glass laser, a ruby laser, analexandrite laser, or a Ti:sapphire laser; a solid laser using crystalsuch as YAG, YVO₄, YLF, or YAlO₃ which is doped with Nd, Tm, or Ho; or asemiconductor laser is preferably used. In addition, a laser oscillationtype may be either continuous oscillation or pulse oscillation. A laserbeam may have a linear shape, a rectangular shape, a circular shape, oran elliptical shape. A wavelength to be used may be a fundamental wave,the second harmonic, or the third harmonic, and is preferably selectedas appropriate by an operator. A scanning direction may be alongitudinal direction, a transverse direction, or an oblique direction.Further, the laser may be scanned back and forth. In addition, theposition of the opening portion 14 is not particularly limited as longas it is not a region provided with the TFT or the wiring, and theopening portion may be appropriately provided. Further, the openingportion 14 may be a hole or a groove having a width.

A cross-section after the aforementioned process is schematically shownin FIG. 1A.

Next, the layer to be peeled 12 is peeled from the substrate 10. Thepeeling is performed under an atmosphere containing a halogen gas. Inthis embodiment mode, an atmosphere of a mixed gas of a ClF₃ gas and aninert gas (He or N₂) is used. In a case of peeling with the human hand,the peeling is performed in a glove box. Alternatively, the peeling maybe performed by using a force of a peeling apparatus provided in asealed chamber. The apparatus is operated with electricity.

In addition, an auxiliary substrate may be attached to the protectivelayer before peeling, to perform peeling with the layer to be peeled 12supported.

As shown in FIG. 18, while the layer to be peeled 12 is peeled from thesubstrate 10 by a physical means 16, a halogen gas is blown to thepeeling layer 11 at the same time. Here, a ClF₃ gas is blown from anozzle 15 at a flow rate of 50 sccm. By blowing a halogen gas to apeeling layer, etching of the peeling layer proceeds, and peeling can beperformed in a short time. In addition, by airflow generated by blowinga halogen gas, peeling can be promoted.

In addition, peeling may be started after exposing the peeling layer toan atmosphere containing halogen for a short time to slightly etch thepeeling layer.

An example of a peeling apparatus is shown in FIG. 2A. The peelingapparatus of FIG. 2A is provided in a sealed chamber, and all parts ofthe peeling apparatus are formed of materials which do not react with ahalogen gas.

FIG. 2A is a perspective view of a peeling apparatus when peelingtreatment is conducted, in which a layer to be peeled is peeled from asubstrate.

A substrate 101 provided with a layer to be peeled and a peeling layeris transferred into a chamber provided with a peeling apparatus by atransfer robot or the like and is fastened by a fast pin 105 provided ona table 102. Further, a vacuum chuck for fastening the substrate 101 tothe table 102 may be provided.

In the peeling apparatus, the position of the substrate is aligned byusing an imaging portion 112 such as a CCD camera, and an edge of alayer to be peeled 150 is clipped from top-back both sides by a chuckportion 109. In the case of attaching an auxiliary substrate to thelayer to be peeled, an edge of the auxiliary substrate is clipped fromtop-back both sides.

The table 102 which fastens the substrate 101 moves in a direction asshown by the arrow in FIG. 2A by a moving mechanism 104 and a movableplate 103.

A chuck elevator mechanism 110 provided with the chuck portion 109 ismoved up and down along with a groove provided in a guide portion 111.After clipping the edge of the layer to be peeled 150 from top-back bothsides by the chuck portion, the edge of the layer to be peeled 150 ispulled upward by using the chuck elevator mechanism 110.

In addition, a nozzle 108 is provided with a plurality of holes, and areaction gas is blown from the holes. The reaction gas is come from asteel cylinder provided at the outside of the chamber through a gasintroduction pipe 107 to be blown from the holes. The nozzle 108 canalso support the peeling by pressing and fasten the substrate 101 sothat the substrate 101 does not move in accordance with the layer to bepeeled which is pulled with the chuck portion 109.

The height of the nozzle 108 can be adjusted by a height controlmechanism 106.

In addition, an atmosphere in the chamber is a halogen gas, which is agas for etching a peeling layer 140. In order to efficiently make thechamber to have an atmosphere of a halogen gas in a short time, a gasintroduction pipe or an exhausting means may be provided.

The chuck elevator mechanism 110 and the moving mechanism 104 arecontrolled by a controlling portion 113 which includes a computer, basedon data from the imaging portion 112 such as a CCD camera.

FIG. 2B shows a cross-section of a periphery of a peeled portion duringpeeling. By blowing an etching gas to the peeled portion, the peelinglayer 140 becomes fragile, and the layer to be peeled 150 becomes easyto be torn off from the substrate 101. Note that, as long as the layerto be peeled 150 can be torn off from the substrate 101, a portion ofthe peeling layer 140 may remain on the layer to be peeled 150.

In addition, the layer to be peeled in the peeled portion may be peeledwith being pressed by a nozzle, which has a cross-section of a wedgeshape.

Since the peeling apparatus shown in FIG. 2A has the fast pin 105, thenozzle 108 stops short of the fast pin 105. Accordingly, in a case ofcompletely peeling the layer to be peeled from the substrate 101,etching is performed by using an atmosphere in the chamber or thereaction gas blown from the nozzle 108. In consideration of easiness oftransfer, the substrate may be transferred outside the chamber withoutpeeling a portion of the layer to be peeled, and later, the layer to bepeeled may be completely peeled from the substrate 101 by peeling theportion of the layer to be peeled.

In this embodiment mode, by forming a metal oxide film (WO_(x)) over ametal film of W which is a peeling layer, the attachment of a peelinglayer and an insulating film made of an oxide material (a film made ofsilicon oxide, silicon oxynitride, or a metal oxide material) becomesweak, and peeling becomes easy to be performed. Then, it becomespossible to easily separate a thin film integrated circuit from asubstrate without completely removing a peeling layer.

Peeling can be smoothly performed by using a method in which a layer tobe peeled is peeled with blowing a halogen gas to a peeling layer to beremoved in an atmosphere containing a halogen gas. Accordingly, apeeling treatment can be automated by using a peeling apparatus shown inFIGS. 2A and 2B.

Then, by transferring the layer to be peeled which has been peeled fromthe substrate 101 to a flexible substrate such as a plastic film, ahigh-performance semiconductor integrated circuit (such as a sending andreceiving circuit including a CPU, a memory, or an antenna) using aflexible substrate can be realized.

Further, when a flexible substrate is used as an auxiliary substrate,peeling from a glass substrate and the transfer to a flexible substrateare completed at once.

According to the present invention, a TFT provided over a glasssubstrate can be transferred to a flexible substrate in a short time.When the flexible substrate to which the TFT is transferred is used, aliquid crystal display device or a light emitting element using theflexible substrate can be realized.

(Embodiment Mode 2)

Though an example of performing the peeling in a halogen gas atmosphereis described in Embodiment Mode 1, an example of performing peeling inan etchant will be described here.

Similarly to Embodiment Mode 1, a peeling layer 21 is formed over aglass substrate 20, and an insulating film and a layer to be peeled 22including a plurality of TFTs, which is provided over the insulatingfilm, are formed. In this embodiment mode, a silicon film is used as thepeeling layer 21. A protective layer 23 is formed in the same manner asin Embodiment Mode 1. The protective layer 23 is formed using a materialwhich does not react with an etchant to be used in a subsequent step,for example, an organic resin.

Subsequently, dry etching or wet etching is performed using a mask. Inthis etching step, an opening portion 24 reaching the peeling layer 21is selectively formed in a region except a region provided with the TFT,a wiring, or the like, so as to expose the peeling layer 21. Inaddition, the position of the opening portion 24 is not particularlylimited as long as it is not a region provided with the TFT or thewiring, and the opening portion may be appropriately provided. Further,the opening portion 24 may be a hole or a groove having a width.

A cross-section after the aforementioned process is shown in FIG. 3A.

Next, the layer to be peeled 22 is peeled from the substrate 20. Peelingis performed in an etchant by soaking the substrate 20 in a liquid tank27 in which a liquid containing halogen is contained. In this embodimentmode, a mixed solution of hydrofluoric acid (HF) and nitric acid (HNO₃)is used as the etchant which can etch silicon. As another etchant foretching silicon, a tetramethylammonium hydroxide solution called TMAH, aKOH solution, an N₂H₄ solution, an NaOH solution, a CsOH solution, orthe like can be used. Further, as another etchant for etching silicon, amixed solution of dimethylsulfoxide and monoethanolamine can be used.

As shown in FIG. 3B, while the layer to be peeled 22 is peeled from thesubstrate 20 by a physical means 26, a reaction liquid (a liquidcontaining halogen) is supplied to the peeling layer 21 from a nozzle 25at the same time. By continuously providing an etchant to a peelinglayer, etching of the peeling layer proceeds, and peeling can beperformed in a short time. In addition, by water flow generated byproviding a reaction liquid, peeling can be promoted.

An etchant including more component which reacts with silicon than thatof the etchant contained in the liquid tank 27 in advance, may beprovided from the nozzle. By discharging the etchant from a nozzle, apeeling layer can be etched in a shorter time. In addition, the useamount of a liquid material can be reduced, comparing with a case ofentirely replacing a solution in the liquid tank 27 every timecompleting one peeling.

Further, an etchant having a higher temperature than that of the etchantcontained in the liquid tank 27 in advance may be provided from thenozzle. By discharging an etchant having a higher temperature from anozzle, a peeling layer can be etched in a short time.

In addition, by pulling out the layer to be peeled from the etchant by aphysical means 26, a peeled portion of the layer to be peeled can beimmediately prevented from being exposed to the etchant. Accordingly, apeeling method of this embodiment mode can be said to be a peelingmethod with few damages to the layer to be peeled.

Then, by transferring the peeled layer to be peeled 22 from thesubstrate 20 to a flexible substrate such as a plastic film, ahigh-performance semiconductor integrated circuit (a sending andreceiving circuit including a CPU, a memory, or an antenna) using aflexible substrate can be realized.

Further, when a flexible substrate is used as an auxiliary substrate,peeling from a glass substrate and the transfer to a flexible substrateare completed at once.

According to the present invention, a TFT provided over a glasssubstrate can be transferred to a flexible substrate in a short time.When the flexible substrate to which the TFT is transferred is used, aliquid crystal display device or a light emitting element using aflexible substrate can be realized.

In addition, this embodiment mode can be freely combined with EmbodimentMode 1. For example, peeling in an etchant becomes possible when thepeeling apparatus described in Embodiment Mode 1 is provided at thebottom of the liquid tank instead of providing to the chamber, thepeeling apparatus is soaked in the etchant, and a nozzle for dischargingthe etchant is provided instead of a nozzle for discharging a gas. Notethat, in this case, materials which do not react with the etchant areused for all parts of the peeling apparatus.

The present invention including the structure will be explained in moredetail in the following embodiment.

[Embodiment 1]

In Embodiment 1, a case of using a thin film integrated circuit as an ICchip will be described.

The IC chip can be roughly divided into three types: a contactless typeIC chip mounted with an antenna (also referred to as a wireless tag), acontact type IC chip provided with a terminal connected to an externalpower source without a mounted antenna, and a hybrid type IC chip whichis a combination of the contactless type and the contact type.

In the case of using the thin film integrated circuit as the contacttype IC chip, the thin film integrated circuit peeled by a peelingmethod of the present invention can be used by being directly mounted onan article.

On the other hand, in the case of using the thin film integrated circuitas the contactless type IC chip or the hybrid type IC chip, theintegrated circuit is preferably used with a mounted antenna. Examplesof a cross-sectional view of the IC chip, on which an antenna ismounted, are shown in FIGS. 4A and 4B. Note that cross-sectional viewsof FIGS. 4A and 4B show the state before peeling the IC chip from asubstrate.

FIG. 4A is a cross-sectional view of an IC chip in which an antenna 232is directly formed over a layer to be peeled including a thin filmintegrated circuit formed of TFTs 201 a and 201 b.

After forming up to wirings 207 a to 207 c of the TFTs, an interlayerinsulating film 231 is formed to cover the wirings 207 a to 207 c. Theinterlayer insulating film 231 can be anything as long as it is aninsulating film obtained by a PCVD method or a coating method. In thisembodiment, the interlayer insulating film is formed by a coating methodusing siloxane polymer.

Subsequently, contact holes are formed in the interlayer insulating film231 to reach the wirings 207 a and 207 c. Then, antennas 232 are formedto be electrically connected to the wiring 207 a or 207 c. As a materialof the antenna 232, a conductive metal material such as Ag, Al, Au, Cu,or Pt can be used. In the case of using Al or Au which has relativelyhigh resistance, the wiring resistance may become of concern. However,the wiring resistance can be reduced by thickening or widening theantenna. Alternatively, antennas may be laminated and covered with amaterial having low resistance. In the case of using a conductivematerial such as Cu, which has a fear to be diffused, an insulating filmis preferably formed to cover a surface provided with an antenna or aperiphery of Cu.

Next, a protective layer 233 is formed to cover the antenna 232.

Subsequently, by using a peeling method described in Embodiment Mode 1or 2, a peeling layer can be removed, so that an IC chip is peeled offfrom a substrate. A peeling method of the invention enables peeling in ashort time and also enables the reduction of damages to a layer to bepeeled.

After that, the peeled IC chip is divided into pieces, and the pieces ofthe IC chip can be used by being mounted on articles or the like.Alternatively, the IC chip can be used by mounting it on an article orthe like after the layer to be peeled is attached to a flexiblesubstrate.

FIG. 4B is a cross-sectional view showing a case of attaching an antennasubstrate 235 provided in advance with an antenna 234, to a substrateprovided with a layer to be peeled including a thin film integratedcircuit formed of TFTs 201 a and 201 b with an adhesive or the like.

As an attaching means of two substrates, an anisotropic conductor 236including dispersed conductors 237 can be used. The anisotropicconductor 236 can be conductive in a region 239 which is provided with aconnection terminal 238 of the IC chip and a connection terminal of theantenna 234, since the conductors 237 are bonded to each other bypressure due to the thickness of each connection terminal. In the otherregion, wirings formed over the substrate are not electrically connectedto each other since a sufficient distance between the conductors iskept. Instead of using the anisotropic conductor, the two substrates maybe attached to each other with an ultraviolet curing resin, two-sidedtape, or the like. Alternatively, ultrasonic bonding can be employed toattach two substrates.

Subsequently, by using a peeling method described in Embodiment Mode 1or 2, a peeling layer can be removed, so that the IC chip is peeled offfrom the substrate. A peeling method of the invention enables peeling ina short time and also enables the reduction of damages to a layer to bepeeled.

After that, the peeled IC chip is divided into pieces, and the pieces ofthe IC chip can be used by being mounted to articles or the like. Inthis case, since the layer to be peeled is fixed on the antennasubstrate 235, the IC chip can be used by being directly mounted on anarticle or the like.

Note that, in a case where the IC chip has a fear of warping due tostress or the like when peeled from the substrate, a protective film ispreferably formed over the antenna substrate 235.

In addition, since the IC chip shown in this embodiment is formed byusing not a silicon substrate but a thin film integrated circuit formedover an insulating substrate, there are fewer limitations on the shapeof a mother substrate, comparing with a chip formed by using a circularsilicon substrate. Therefore, cost of the IC chip can be reduced. An ICchip of the present embodiment uses, unlike a chip formed by using asilicon substrate, a semiconductor film having a thickness of 0.2 μm orless, typically 40 nm to 170 nm, preferably 50 nm to 150 nm, as anactive region; accordingly, the IC chip becomes very thin. As a result,even when the IC chip is mounted on an article, the existence of thethin film integrated circuit is hard to be recognized, which preventsfalsification such as forgery.

In addition, the IC chip shown in this embodiment has, comparing with achip formed by using a silicon substrate, less concern about radio waveadsorption. Therefore, a signal can be received with high sensitivity.Further, the thin film integrated circuit without including a siliconsubstrate has a light transmitting property. As a result, the thin filmintegrated circuit can be applied to various articles. For example, evenwhen the integrated circuit is mounted on a printing surface of anarticle, the design is not harmed.

The present embodiment can be freely combined with Embodiment Mode 1 or2.

[Embodiment 2]

In Embodiment 2, a structure of an IC chip manufactured by a peelingmethod according to the present invention will be explained.

FIG. 5A is a perspective view of one mode of an IC chip. Referencenumeral 920 denotes an integrated circuit and 921 denotes an antenna.The antenna 921 is electrically connected to the integrated circuit 920.Reference numeral 922 denotes a flexible substrate and 923 denotes acover material. The integrated circuit 920 and the antenna 921 aresandwiched between the flexible substrate 922 and the cover material923.

After forming an integrated circuit and an antenna over a glasssubstrate, peeling may be performed by using a peeling method of thepresent invention to transfer the integrated circuit and the antenna toa flexible substrate. Alternatively, after forming an integrated circuitover a glass substrate, an antenna provided in a cover material may bemounted to be electrically connected to the integrated circuit, andpeeling may be performed by a peeling method of the invention. Then, theintegrated circuit and the antenna may be transferred to a flexiblesubstrate. A peeling method of the invention enables peeling in a shorttime and also enables the reduction of damages to a layer to be peeled.

Next, FIG. 5B is a block diagram showing one mode of a functionalstructure of the IC chip shown in FIG. 5A.

In FIG. 5B, reference numeral 900 denotes an antenna; 901, an integratedcircuit; and 903, a capacitor formed between terminals of the antenna900. The integrated circuit 901 has a demodulation circuit 909, amodulation circuit 904, a rectification circuit 905, a microprocessor906, a memory 907, and a switch 908 for giving load modulation to theantenna 900. The number of memories 907 is not limited to one, and aplurality of memories such as an SRAM, a flash memory, a ROM, and anFRAM (registered trademark) can be used.

A signal sent from a reader/writer as an electric wave is converted intoan alternating electric signal by electromagnetic induction in theantenna 900. The demodulation circuit 909 demodulates the alternatingelectric signal to send it to the microprocessor 906 in a subsequentstage. The rectification circuit 905 generates power source voltage byusing the alternating electric signal to supply it to the microprocessor906 in the subsequent stage. The microprocessor 906 carries out variouskinds of arithmetic processing in accordance with the inputted signal.The memory 907 stores a program and data used in the microprocessor 906.In addition, the memory 907 can be used as a working area in thearithmetic processing.

When data is sent from the microprocessor 906 to the modulation circuit904, the modulation circuit 904 can control the switch 908 to apply loadmodulation to the antenna 900 in accordance with the data. As a result,the reader/writer can read out the data from the microprocessor 906 byreceiving an electric wave of the load modulation given to the antenna900.

The IC chip does not necessarily have the microprocessor 906. Thetransmission system of a signal is not limited to the foregoingelectromagnetic coupling system as shown in FIG. 5B. The electromagneticinduction system, a microwave system, or another transmission system maybe used.

Since an IC chip having an antenna can transmit information, the IC chipcan be used as a wireless memory or a wireless processor.

In addition, a security system can be established using the IC chiphaving an antenna. The following is a general explanation of the system.

Authentication is precisely performed by combining a plurality ofcard-shaped recording media 1001, on each of which an antenna 921 and anintegrated circuit 920 including a microprocessor are mounted.

FIG. 6A is a perspective view of a plurality of card-shaped recordingmedia, which are brought together with a ring. Though an antenna 921 andan integrated circuit 920 are shown in FIG. 6A for clear presentation,they are preferably sealed with a colored film so as not to be seen, inthe interests of crime prevention.

Card-shaped recording media 1001 to 1005 each record differentidentification data. Then, by holding the recording media to a readerprovided to a door which is provided with a key control system, allidentification data is read out, and locking and unlocking of the keycontrol system are performed based on the read-out data. In addition, acard-shaped recording medium 1006 for a warning signal is broughttogether with a ring as well, and the card-shaped recording media 1001to 1005 other than the card-shaped recording medium for a warning signalare held to the reader. When a person who does not know this systemholds the card-shaped recording medium 1006 for a warning signal, inaddition to the other card-shaped recording media, to a reader, awarning signal rings, or calling to a security agency is conducted.Since the card-shaped recording media are brought together with a ring,the order of the card-shaped recording media can be changed. Forexample, a card-shaped recording medium positioned at the top can bemoved to the back.

An example of using six recording media including five card-shapedrecording media for authentication and one card-shaped recording mediumfor a warning signal is shown in FIG. 6A; however, the number of therecording media is not particularly limited as long as there are threeor more recording media including at least two card-shaped recordingmedia for authentication and one card-shaped recording medium for awarning signal.

In addition, instead of using the card-shaped recording medium for awarning signal, a card for interrupting a signal from a reader may beused. For example, when the card for interrupting a signal from areader, which is interposed between two card-shaped recording media forauthentication, is held to a reader, the identification data of only onecard-shaped recording medium for authentication is read out.

An example of bringing together a plurality of the card-shaped recordingmedia with a ring is shown in FIG. 6A; however, there is no particularlimitation, and a plurality of card-shaped recording media having a cardsize may put in a wallet or a card case.

All the identification data is not recorded in one card-shaped recordingmedium. By dividing the identification data into a plurality of cardsand mixing a card for a warning signal, security is improved. Inaddition, by using a plurality of cards, more identification data can berecorded.

A plurality of card-shaped recording media is preferably provided by atleast a plurality of administrators. An example of a block diagram ofthe control system is shown in FIG. 6B.

The security system shown here is a system which includes a plurality ofcard-shaped recording media, an information reader (reader) for readingout the information recorded in the recording media, and a key controlsystem which decides whether or not to authorize a user of the recordingmedia to enter a predetermined area based on the information read outfrom the information reader.

This security system is a system in which a first identification data isrecorded in a first card-shaped recording medium and a secondidentification data is recorded in a second card-shaped recordingmedium, and which authorizes the user to enter a predetermined area onlywhen the first and the second identification data is read out at thesame time by the information reader.

The user takes the first card for authentication from a firstadministrator and the second card for authentication from a secondadministrator. The first and the second administrators are, for example,manufacturers of different card-shaped recording media from each other.The identification data provided from the first and the secondadministrators are different from each other. Since cards are providedfrom a plurality of administrators, even when the information of oneadministrator is leaked or one card is forged, a key control system canbe continuously controlled.

An alarm card for a warning signal is supplied from either or both ofthe first and the second administrators. A plurality of supplied cardseach has a different design. Cards for authentication and an alarm cardare designed so that a person except the user supplied with the cardscannot identify the difference of the cards by appearances.

The user possesses the first card, the second card, and the alarm card.When the cards with the right combination (here, the combination of thefirst and the second cards) are held to a reader/writer, authenticationis completed. If the cards with the wrong combination (for example, thefirst card and the alarm card) are held to the reader/writer,authentication is not made.

The present embodiment can be freely combined with Embodiment Mode 1,Embodiment Mode 2, or Embodiment 1.

[Embodiment 3]

In Embodiment 3, the application of a thin film integrated circuit shownin the aforementioned embodiment modes or the embodiments will bedescribed. A thin film integrated circuit peeled from a substrate can beused as an IC chip. For example, an IC chip 210 can be used by providingit to paper money, coins, securities, bearer bonds, certificates (adriver's license, a certificate of residence, or the like, see FIG. 7A),packing containers (wrapping paper, bottles, or the like, see FIG. 7B),recording media such as DVD software, a CD, and a video tape (see FIG,7C), vehicles such as a car, a motorcycle, and a bicycle (see FIG. 7D),personal belongings such as a bag and glasses, foods, clothing,commodities, electronic devices, or the like. The electronic devicesrefer to a liquid crystal display device, an EL display device, atelevision device (also called TV or TV sets), a cellular phone, and thelike.

An example of mounting the IC chip 210 on a cellular phone is shown inFIG. 7E. The IC chip 210 having an antenna which corresponds to afrequency different from that of a transmitting and receiving antenna ofthe cellular phone may be mounted, by which conversation, mail exchange,or the like can be made.

The IC chip 210 is mounted on an electronic device such as a cellularphone for person authentication. Then, the electronic device can be usedfor authentication at an automatic ticket gate, at a gate of anexhibition hall or a laboratory, as a key to the front door, or forkeyless entry to a car.

The IC chip can be fixed to an article by attaching to a surface orembedding thereinto. For example, in a case of a book as shown in FIG.7F, the IC chip may be embedded in a piece of paper; or in a case of apackage made from an organic resin, the IC chip may be embedded in theorganic resin. Forgery can be prevented by providing an IC chip to eachof the paper money, coins, securities, bearer bonds, certificates, andthe like. The efficiency of an inspection system or a system used in arental shop can be promoted by providing an IC chip to each of thepacking containers, recording media, personal belongings, foods,clothing, commodities, electronic devices, and the like. By providing anIC chip to the vehicles, counterfeits or theft can be prevented.

The present embodiment can be freely combined with Embodiment Mode 1,Embodiment Mode 2, Embodiment 1, or Embodiment 2.

By a manufacturing method of the present invention, a thin filmintegrated circuit including a TFT with high performance can be peeledfrom a glass substrate in a short time. In addition, the thin filmintegrated circuit including a TFT can be transferred to a flexiblesubstrate. According to the invention, mass production is possible, inwhich many thin film integrated circuits are formed over one large sizedsubstrate.

This application is based on Japanese Patent Application serial no.2005-056308 filed in Japan Patent Office on Mar. 1, 2005, the entirecontents of which are hereby incorporated by reference.

What is claimed is:
 1. A manufacturing method of a semiconductor device,comprising: providing a substrate and a layer to be peeled bonded to thesubstrate via a peeling layer; and using an apparatus to hold thesubstrate and to peel the layer to be peeled from the peeling layer byapplying traction to the layer to be peeled while a fluid is between thepeeling layer and the layer to be peeled, wherein the fluid generates achemical reaction that weakens bonding between the layer to be peeledand the peeling layer ,and wherein the traction is applied while thesubstrate and the layer to be peeled are immersed in the fluid.
 2. Themanufacturing method of a semiconductor device according to claim 1,wherein the layer to be peeled is separated from the substrate withoutcompletely removing the peeling layer.
 3. The manufacturing method of asemiconductor device according to claim 1, wherein most of the peelinglayer remains on the substrate after the layer to be peeled is separatedfrom the substrate.
 4. The manufacturing method of a semiconductordevice according to claim 1, wherein the fluid is an etchant.
 5. Themanufacturing method of a semiconductor device according to claim 1,wherein the fluid comprises water molecules.
 6. The manufacturing methodof a semiconductor device according to claim 1, wherein the fluid iscontinuously supplied from a nozzle while the layer to be peeled isbeing peeled from the peeling layer.
 7. The manufacturing method of asemiconductor device according to claim 1, wherein the layer to bepeeled includes transistors.
 8. The manufacturing method of asemiconductor device according to claim 1, wherein the fluid generatesthe chemical reaction that weakens the bonding between the layer to bepeeled and the peeling layer by breaking chemical bonds.
 9. Amanufacturing method of a semiconductor device, comprising: providing asubstrate and a layer to be peeled bonded to the substrate via a metalfilm of a metal, with an insulating film between the layer to be peeledand the metal film, and with a metal oxide film of an oxide of the metalbetween and in contact with each of the metal film and the insulatingfilm; and using an apparatus to hold the substrate and to peel the layerto be peeled from the metal film by applying traction to an edge of thelayer to be peeled by clipping by a chuck while a liquid is between themetal film and the layer to be peeled, wherein the insulating filmcomprises oxygen, and wherein the liquid generates a chemical reactionthat weakens bonding between the layer to be peeled and the metal film.10. The manufacturing method of a semiconductor device according toclaim 9, wherein a thickness of the insulating film is more than twice athickness of the metal film.
 11. The manufacturing method of asemiconductor device according to claim 9, wherein separation betweenthe layer to be peeled and the metal film occurs inside the metal oxidefilm.
 12. The manufacturing method of a semiconductor device accordingto claim 9, wherein separation between the layer to be peeled and themetal film occurs at an interface between the metal oxide film and theinsulating film.
 13. The manufacturing method of a semiconductor deviceaccording to claim 9, wherein separation between the layer to be peeledand the metal film occurs at an interface between the metal oxide filmand the metal film.
 14. The manufacturing method of a semiconductordevice according to claim 9, wherein the layer to be peeled is separatedfrom the substrate without completely removing the metal film.
 15. Themanufacturing method of a semiconductor device according to claim 9,wherein most of the metal film remains on the substrate after the layerto be peeled is separated from the substrate.
 16. The manufacturingmethod of a semiconductor device according to claim 9, wherein theliquid is an etchant.
 17. The manufacturing method of a semiconductordevice according to claim 9, wherein the liquid comprises watermolecules.
 18. The manufacturing method of a semiconductor deviceaccording to claim 9, wherein the liquid is continuously supplied from anozzle while the layer to be peeled is being peeled from the metal film.19. The manufacturing method of a semiconductor device according toclaim 9, wherein the layer to be peeled includes transistors.
 20. Themanufacturing method of a semiconductor device according to claim 9,wherein the liquid generates the chemical reaction that weakens thebonding between the layer to be peeled and the metal film by breakingchemical bonds.
 21. The manufacturing method of a semiconductor deviceaccording to claim 9, wherein a thickness of the metal oxide film of theoxide of the metal is about 2 nm to 5 nm.
 22. The manufacturing methodof a semiconductor device according to claim 9, wherein the traction isapplied to a corner portion of the edge of the layer to be peeled. 23.The manufacturing method of a semiconductor device according to claim 9,wherein the traction is applied while the substrate and the layer to bepeeled are immersed in the liquid.
 24. A manufacturing method of asemiconductor device, comprising: providing a substrate and a layer tobe peeled bonded to the substrate via a tungsten film, with aninsulating film between the layer to be peeled and the tungsten film,and with a tungsten oxide film between and in contact with each of thetungsten film and the insulating film; and using an apparatus to holdthe substrate and to peel the layer to be peeled from the tungsten filmby applying traction to an edge of the layer to be peeled by clipping bya chuck while a liquid is between the tungsten film and the layer to bepeeled, wherein the insulating film comprises silicon, nitrogen, andoxygen, and wherein the liquid generates a chemical reaction thatweakens bonding between the layer to be peeled and the tungsten film.25. The manufacturing method of a semiconductor device according toclaim 24, wherein a thickness of the insulating film is more than twicea thickness of the tungsten film.
 26. The manufacturing method of asemiconductor device according to claim 24, wherein separation betweenthe layer to be peeled and the tungsten film occurs inside the tungstenoxide film.
 27. The manufacturing method of a semiconductor deviceaccording to claim 24, wherein separation between the layer to be peeledand the tungsten film occurs at an interface between the tungsten oxidefilm and the insulating film.
 28. The manufacturing method of asemiconductor device according to claim 24, wherein separation betweenthe layer to be peeled and the tungsten film occurs at an interfacebetween the tungsten oxide film and the tungsten film.
 29. Themanufacturing method of a semiconductor device according to claim 24,wherein the layer to be peeled is separated from the substrate withoutcompletely removing the tungsten film.
 30. The manufacturing method of asemiconductor device according to claim 24, wherein most of the tungstenfilm remains on the substrate after the layer to be peeled is separatedfrom the substrate.
 31. The manufacturing method of a semiconductordevice according to claim 24, wherein the liquid is an etchant.
 32. Themanufacturing method of a semiconductor device according to claim 24,wherein the liquid comprises water molecules.
 33. The manufacturingmethod of a semiconductor device according to claim 24, wherein theliquid is continuously supplied from a nozzle while the layer to bepeeled is being peeled from the tungsten film.
 34. The manufacturingmethod of a semiconductor device according to claim 24, wherein thelayer to be peeled includes transistors.
 35. The manufacturing method ofa semiconductor device according to claim 24, wherein the liquidgenerates the chemical reaction that weakens the bonding between thelayer to be peeled and the tungsten film by breaking chemical bonds. 36.The manufacturing method of a semiconductor device according to claim24, wherein the traction is applied while the substrate and the layer tobe peeled are immersed in the liquid.